National Repository of Grey Literature 57 records found  1 - 10nextend  jump to record: Search took 0.01 seconds. 
Preparation of graphene membranes for Ga deposition
Severa, Jiří ; Bartošík, Miroslav (referee) ; Mach, Jindřich (advisor)
This bachelor’s thesis deals with the production of graphene membranes, which would be suitable for the deposition of gallium atoms. In the first part is characterized graphene. The second part is focused on preparation and improvement the production of graphene layers via atomically flat Cu foils. In the third part are described graphene membranes, techniques of their production and specific applications of graphene membranes. The fourth part introduced interface between gallium and graphene layers. The fifth part is the practical part. Graphene was grown on different Cu foils which resulted in higher quality graphene grown on smooth foils. Subsequently, the production of graphene membranes and deposition of gallium atoms were done.
Optimization of devices for deposition GaN nanostructures
Šimek, Daniel ; Voborný, Stanislav (referee) ; Mach, Jindřich (advisor)
This bachelor thesis deals with the automation of sources for the deposition of GaN nanocrystals used at the Institute of Physical Engineering. For the purpose of the thesis, the mechanism of automatic control of the gallium effusion cell shutter was designed and constructed and the control electronics containing components enabling automatic switching of the ion atomic source of nitrogen ions. In addition, samples of GaN nanocrystals on four different substrates that were studied for cold electron emission were prepared by the method of ion beam assisted molecular beam epitaxy IBA-MBE. The results of the measurement are discussed in the conclusion.
Optimization of Carbon atomic source for graphene layer growth by MBE method
Liška, Petr ; Bartošík, Miroslav (referee) ; Mach, Jindřich (advisor)
This bachelor’s thesis deals with the development and optimization of an atomic source of carbon atoms with the thermal energy (0.1÷1 eV). An atomic beam in the conditions of ultrahigh vacuum is considered to be a suitable source of superior graphene layers also due to the high purity of the method. The first part of this work describes graphene as a material and the method of molecular beam epitaxy. The second part is dedicated to the description of an assembly of the carbon source and its optimization which also concludes with experimental data obtained from measurement of the deposited carbon layers on various substrates (Cu, Ge, Al2O3, SiO2).
Deposition of GaN nanocrystals with Ga droplets
Novák, Jakub ; Voborný, Stanislav (referee) ; Mach, Jindřich (advisor)
This bachelor thesis deals with preparation and characterization of Ga structures and GaN nanocrystals. In the theoretical part, properties and applications of GaN are introduced. Further, some substrates for the growth and some techniques used for manufacturing of these structures are stated. Further, is also mentioned the photoluminiscence of GaN. The experimental part deals with preparation of Ga and GaN structures and combination of both. These structures were further analyzed by various methods such as XPS, SEM or photoluminiscence.
Optimization of thermal dissociation atomic hydrogen source for use SEM
Melichárek, Václav ; Polčák, Josef (referee) ; Mach, Jindřich (advisor)
The focus of this bachelor's thesis is the optimization of a thermal dissociation monoatomic hydrogen source. The project entailed the design and construction of a new control electronics for the thermal dissociation source, because the source has been powered using universal laboratory power supplies until now. The thesis begins with a brief introduction into the interaction of graphene with monoatomic hydrogen, the operational principle and construction of the monoatomic hydrogen source. Furthermore, the requirements on the design of the electronics are specified. A more detailed analysis of possible solutions, and the selection of the optimal solution were also conducted. The practical part discusses the conceptual designs in detail and describes the selection of the optimal solution. It follows by elaborating on the implementation of the control electronics in detail, its design and construction, and the electrical circuit in particular.
Schottky solar cells with interface graphene/si modified by GaN
Mohelský, Ivan ; Voborný, Stanislav (referee) ; Mach, Jindřich (advisor)
This bachelor thesis deals with fabrication and characterization of Schottky solar cells with graphene/silicon junction. For this study, the I-V characteristic measuring device was designed and assembled. Also, the graphene/silicon junction was modified by GaN nanocrystals and properties of such a solar cell was studied.
Design of manipulator for ultrahigh electron microscope
Caesar, Radek ; Mach, Jindřich (referee) ; Bábor, Petr (advisor)
The main purpose of this thesis is mechanical design of a manipulator for an ultra-high vacuum scanning electron microscope (UHV SEM), being currently developed by TESCAN ORSAY HOLDING a.s. in cooperation with the Institute of physical engineering FME BUT. The manipulator is supposed to be able to handle with specimens in so-called preparation chamber, which the specimens are put in before placing into the analytic chamber. In the preparation chamber the surface finishing and also other operations are made. In the theoretical part some of the technologies used in vacuum engineering, especially various principles of pressure measurement and gas pumping, are described. Besides, the thesis is focused on a brief description of UHV SEM being developed and the methods of specimen preparation. The practical part deals with the concept and the mechanical design of manipulator itself.
Study of electric charge propagation across an insulating surface by Kelvin probe force microscopy at different relative humidity
Tripský, Andrej ; Mach, Jindřich (referee) ; Bartošík, Miroslav (advisor)
This Bachelor thesis is focused on experimental study of diffusion coefficient depending on the relative humidity and surface modification measured by Kelvin Probe Force Microscopy. In the experiment has been investigated gold and silicon dioxide structures. The data were fitted and coefficient of diffusion, conductivity and resistivity for different conditions were found based on created model.
Deposition and characterization of GaN nanocrystals with a metal core
Čalkovský, Vojtěch ; Čech, Vladimír (referee) ; Mach, Jindřich (advisor)
Tato diplomova prace se zabyva prpravou a charakterizac GaN nanokrystalu s kovovym jadrem. V teoreticke casti teto prace je predstaven material GaN se svymi vlastnos- tmi a aplikacemi. Dale jsou uvedeny substraty pro rust a jednotlive mechanismy rustu GaN nanokrystalu. V dalsm jsou popsany kovove nanocastice a jejich opticke vlastnosti umoznujc zesilovan fotoluminiscence na zaklade interakce plasmonu a GaN. Experi- mentaln cast se zabyva prpravou GaN nanokrystalu s Ag jadrem ve ctyrech krocch. Prvne jsou Ag nanocastice naneseny na substrat Si(111). Nasledne se nechaj zoxidovat. Tretm krokem je depozice Ga a poslednm je nitridace. Jednotlive kroky byly opti- malizovany a analyzovany ruznymi metodami, jako je XPS, SEM, fotoluminiscence a Ramanova spektroskopie.
Optimization of device for measurement field emission from GaN nanocrystals surface
Horák, Stanislav ; Kromka, Alexander (referee) ; Mach, Jindřich (advisor)
This diploma thesis deals with the design and optimization of the device for measurement of field emission from gallium nitride (GaN) nanocrystals surface. The first part of the thesis is the topic review, which contains the introduction to the problematics of field emissio focused on GaN. Then there were designed, constructed and optimized two versions of the device for the measurement of field emission. Through the optimization phase, the first successful test has been performed with zinc oxide (ZnO) nanowires. Simultaneously GaN nanocrystals were fabricated on the silicon substrate Si(111) with 2 nm of silicon dioxide SiO2 and also on the copper foil covered by graphene by molecular beam epitaxy (MBE). In the last chapter, there are presented the results of the measurement for emission of GaN nanocrystals. Finally, this study is comparing results with the current research in the area of field emission, which displays the improved characteristics for field emission of GaN nanocrystals on the copper foil covered by graphene.

National Repository of Grey Literature : 57 records found   1 - 10nextend  jump to record:
See also: similar author names
15 MACH, Jan
14 MACH, Jiří
3 Mach, Jakub
15 Mach, Jan
14 Mach, Jiří
2 Mach, Jonáš
Interested in being notified about new results for this query?
Subscribe to the RSS feed.